[Validation of a questionnaire to quantify the risk for skin cancer]

Currently, strategies are needed to identify the population at risk for skin cancer in order to implement prevention and for early diagnosis. There are no validated Spanish language instruments to measure skin cancer risk.

To design and validate a self-applied questionnaire to quantify the risk of melanoma and non-melanoma skin cancer in a Mexican population.

A self-applied questionnaire was designed to measure risk factors for skin cancer. Face and content validity was assessed by five experts in skin cancer. The value of each item was weighted according to the relative risk of the risk factors. The questionnaire was applied to extreme groups in order to measure the construct validity. Reliability was evaluated using test-retest method two weeks after the first application.

The questionnaire was applied to patients with (n = 147) and without (n = 249) skin cancer from the Dermatologic Center "Dr. Ladislao de la Pascua". The total score of the questionnaire was different in both groups (U = 2,104.5, p = 0.0001) and ROC curve determined that five points or more equals high risk for skin cancer (area 0.964; 95% CI: 0.946-0.981; p = 0.0001). The reliability of the instrument was 0.971 (95% CI: 0.943-0.986; p = 0.0001).

This is the first Spanish language questionnaire valid to measure risk of skin cancer, whose application at the population level would be useful to identify high-risk individuals who need preventative interventions.